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近日在练眼镜蛇滚转（Rolling Harriers），在RCU上看到IMAC UNLIMITED冠军Mark Leseberg, Jr.的一篇关于该特技的文章，花了一天时间把它译成中文，希望各位模友从中受益。帮忙顶一下.。
翻译水平有限，有错漏的地方请指正。
基础：当我们能够很正确的作出眼镜蛇式滚转时，这个动作是最优美的最感人的。当吊机及扭力滚深深打动人的时候，人们往往会认为眼镜蛇式滚转仅仅是一个普通的有一点仰角的滚转，然而他们所不知道的是眼镜蛇式滚转需要无数小时的练习，配合和调速才能有效的控制这个特技动作。
理解副翼滚转对于正确理解眼镜蛇式滚转是非常重要的。将眼镜蛇式滚转理解为一个副翼滚转跟着下一个副翼滚转接着下一个这个概念很重要。如果我们没有第一个滚转的概念，那莫将不可能开此练习眼镜蛇式滚转。对于大多数人来说，最简单开始练习的方法是从你认为熟悉的旋转方向开始练习。就是说不管向左或者向右转区别不大。
我感到最好还是飞机滚装的方向与转圈方向相反，即向左滚转时飞机向右转圈或右滚转时向左转圈，这样作的好处是更有表现力且可以在眼镜蛇式滚转过程中通过一个眼镜蛇式飞行翻转滚转方向。
如果要实现这个动作，我们必须要画一条贯穿飞机的线，这条线从整流罩的尖端开始直到方向舵的中位或者拉力的中线，我们通常叫这条线为零线。我门必须在这个特技动作中始终维持这条零线而不需要顾及飞机的攻角。这样我们就引申出一个问题就是旋转速度。很多人问我是如何维持飞机旋转的速度的，其实很简单：我开始练习的时候就选择了一个旋转速度，并且在每个练习阶段中都保持这个速度，作为初学者，选择一个比较慢的旋转速度是至关重要的。
我们首先从一圈中的前90度开始，降低飞机的速度直到飞机头部抬起7－10度，这样做的目的是我们要在飞机停止之前使飞机转动起来，一旦飞机停止了，那莫飞机的机翼与副翼将失去作用。其实眼镜蛇式滚转特技就是在飞机将要停止的时候利用巨大的机翼的动量与拉力进行飞行。我们在练习日中首先要订立一个目标，例如：我今天必须完成4个90度的眼镜蛇式滚转，在重复一次，我们要先会爬再学行走。
在特技动作中飞机转到第一个90度时最重要的是时间同步，你必须在飞机停止前打全方向舵，而副翼必须保持恒定来维持飞机转动，升降舵在这个时候可以用来控制飞机向左或向右。
一旦我们成功的掌握滚转的第一个90度，我们就可以进而练习飞机转动180度了，当飞机转动接近180度时，我们必须松开方向舵而推足够的升级舵，使飞机能维持一个大的仰角，而这个时候，我们就用方向舵来控制飞机左右。
当飞机转动通过279度时，我们就要松开升降舵而打足够的反方向的方向舵，这是通过升降舵控制飞机左右。
这个特技转一周的结束是以接近垂直的眼镜蛇式飞行为标志的，这是用升降舵控制仰角，用方向控制左右。
当我们成功转动180度时，很多人会放弃的，其实我们已经成功了一般了。
所有剩下来得就是时间的同步了。如果你已经练习了0－180度的特技，那没你一定对这个特技中时间同步的难度有一个了解了，我们必须充满信心，因为即使范错，飞机只是会机头往下掉，如果飞机足够高的话，是很安全的。从这个时候开此，结果完全取决于我们自己了。没有一个人能够告诉你如何才能成功，我做的所有一切只是一个基础，而且我没有足够强调基础和眼镜蛇式飞行的由来。但是我可以告诉大家，我用了200个起落来练习该特技，还有在模拟器上花了无数小时的练习。
飞机的设定也是非常重要的，在3D飞行中，我用140％的副翼，升降和方向舵。用50－70％的指数设定，我用一个三段开关来控制这些比率，一个是正常飞行比率，另外两个是3D设定。我感决到拨动这些开关会影响我们的飞行动作，我也经常听说拨动开关造成坠机。
我飞机上的副翼是最大的，它从翼根到翼尖，且有45度的角度，这样可以实现非常高的转速，我也推荐别人则样设定。大的副翼还可以在事故出现时停止飞机的转动或反方向转动。利用合适的飞机来练习这个是很必要的。当然我们的飞机要有轻的机身，强大的动力，直径大的浆，这样我们更能实现高特技。
当我们掌握了眼镜蛇式飞行的基本动作后，我们就可以提高转动速度了，而且我们要练习通过条件反射改变动力来灵活调整飞机的 高度，而非通过其他舵面控制。其实条件反射就是一种感觉，是对动力，舵面和飞机状态的综合感觉。当然这样所很难理解，但是当你有250个飞行起落时，我们就会理解他的含义了。
到这个阶段，眼镜蛇式飞行的所有动作已经练习了，现在我们可以练习反方向旋转了。小心这是一个危险的游戏，我们有可能放弃，我练习这个两年了才能自由飞行中灵活使用该动作。重复练习不要灰心。
结论：我坐在这里很轻松为你们解释这个特技，不过最好的方法是在模拟器里练习。如果你能在模拟器里实现该特技，在现实飞行也应该可以实现。在模拟器里不断摔机把，因为那不需要成本。还要经常看其他高手的飞行录像，找一个你喜欢的偶像飞机师，尽量模仿他的动作。永远记住：练习不会达到完美，只有完美的练习才能到达到完美。
Courtesy of Mark Leseberg, Jr.
原文如下：
Rolling Harriers: The Basics
When done properly, the Rolling Harrier maneuver is one of the most graceful and impressive of the 3D maneuvers. While many are impressed by hovering or the torque roll, and may look at the rolling harrier as a nothing more than a normal roll that is at a slight angle. What they do not know is that it takes countless hours of practice, coordination, and timing to get the control inputs down to perform this maneuver properly. While every pilot has there own little "tricks" that they use for practice, I will give you an overview of how I like to perform this maneuver.
It is very important to understand the common maneuver that makes this 3D action of the rolling harrier take place - the aileron roll. It is important to understand that the starting point of this maneuver is with one aileron roll followed by another, and another. To start practicing the rolling harrier would be impossible without the concepts of first the roll, then the rolling circle. For most people, the simplest way to begin to practice is to start by rolling in your most preferred direction. This can be to the right or left as it doesn't make much difference.
I feel that you can gain the most by rolling the aircraft to the outside of the turn. (i.e. rolling left and turning right or rolling right and turning left) My reason for doing this is for better presentation and to be able to reverse the roll direction midway through a Harrier Flight.
Presentation in this maneuver should be maintained by drawing a line through the aircraft, from the tip of the spinner, to the center portion of the rudder, or the center of thrust. Most commonly referred to as the Zero Line. This Zero Line is a perfect line that should be maintained throughout the maneuver regardless of the Angle of Attack. This brings up the point of Roll Rates. I have been asked by many people, how I keep up with the roll rate of the aircraft? It is very simple; I picked one roll rate and stuck with that rate for all practice sessions. In the beginning, is vital that you start slowly!
Begin with the first 90 degree section of the roll. Slow the aircraft until the nose is up about 7-10 degrees. The objective here is to begin the roll before the stall. Once the aircraft is stalled, the wing is no longer flying and the ailerons become less effective. The entire appeal to this maneuver is the sheer fact that the airplane should be stalled, but is flying on the MOMENTUM of the mass of the wings, and the thrust generated. Start with a goal for the days flying. For example, I want to accomplish a four-roll Rolling Harrier of 90 degrees. Once again, you have to crawl before you can walk.
The timing is critical as the first 90 degrees of the maneuver you are holding full rudder while the plane is stalled. The ailerons are held steady to maintain a constant roll rate. The elevator is used to steer the plane left or right at that split second.
Once we have attained the first 90 degrees of the roll, I will then proceed to the 180 degree point. As you approach 180 degrees you have relaxed the rudder and are inverted with as much down elevator as you need to maintain the stalled angle of attack. At this point the rudder is used to steer the model.
As you pass through 270 degrees you have relaxed the elevator and now have full opposite rudder input and again are using the elevator to steer the model.
The completion of the maneuver ends with the model upright in a harrier attitude using up elevator to control the angle and rudder to steer.
As soon as the 180 degree point is attained, this is where most people give up on this maneuver. You are more than 50% of the way there.
All that is left is TIMING. If you have practiced the 0-180 degree portion of the Rolling Harrier, you have started with the TIMING aspect of what makes this maneuver so difficult. You are there, but just lack the confidence to finish because you made one mistake and the airplane flies off heading, but we started relatively high and slow. From here on out, it is up to you how bad you want it. No one person can teach you how to finish. All I can do is help you with the basics, and can't emphasize enough to learn the basics and what the Rolling Harrier is derived from. It took me 200 flights and countless hours on the simulator to understand the dynamics of the Rolling Harrier.
Rolling Harriers: The Finer Points
Aircraft setup is very important to learning and understanding what your model is doing at any given time. In the 3D setup on my transmitter, I have 140% ailerons, 140% elevator and 140% rudder. These values are the maximum that are allowed, but are toned down to match the pattern rates near neutral. (i.e.. between 50-70% expo) I fly my aircraft on one switch with two rates. One being Pattern and the other being 3D. It is my feeling that the flipping of switches deters from the task at hand, and as we have all either seen or heard, can cause a crash.
The ailerons on my aircraft are among the biggest out there. They span near the entire length of the wing with 45 degrees of throw in either direction. This is a very high roll rate, that I challenge anyone to match. It also aids in the ability to stop the Rolling Harrier in an instant, and begin in the opposite direction of rotation. It is very important to practice this with an airplane that is suited for this type of flight. Preferably an aircraft that is light, with high power to weight. The bigger the diameter of the prop, the more stable your high alpha maneuvers.
Once you have mastered the Basics of Rolling Harrier flight, it is time to start increasing the roll rate, and developing faster reflexes to to changing altitude via power applications rather than control inputs. Most people think that the control value is what keeps the aircraft at a certain altitude. To tell you the truth, it is a combination of power application, control input, and feeling of the moment. I know that it may seem to much, but after 250 flights, you won't even think about it and will be explaining it to you kids some day.
Rolling Harriers: Going the Opposite Direction
View the Video of
Mark Leseberg at
Tucson Shootout
*courtesy of ScaleAerobatics.com OK, we have the Rolling Harrier all practiced up and now we are ready to go the opposite direction. Get ready for an amazing "mind game" that will make you want to give it up. I have been working on this for two years, and finally have found how to present it well in the Freestyle Program. It is time to repeat the entire process over again while trying to maintain the ability to hold the transmitter without throwing it.
Rolling Harriers: Conclusion
It is very easy for me to site here and explain to you what happens in this maneuver, but the best way is to practice it in the simulator. If you can do it on the simulator, it is possible in real life. I Guarantee it! Go and crash all the airplanes you like on the simulator. It sure is cheaper than a 30-40% aircraft. Watch all the video you can, and emulate the Rolling Harrier from your favorite pilot. Practice doesn't make perfect, Perfect Practice makes Perfect!
Courtesy of Mark Leseberg, Jr.
www.marklesebergjr.com
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发表于 2004-8-4 05:10
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